Accuracy of Left Bundle Branch Block Chronology and Electrocardiography Criteria for Acute Myocardial Infarction
José Nunes de Alencar1, Gleydson Wesley Freire Lima1, Haissa Assad Dos Santos Geraldo1
1Instituto Dante Pazzanese de Cardiologia, São Paulo, SP - Brasil.
Insights
New or old left bundle branch block (LBBB) does not predict acute myocardial infarction (AMI). Modified Sgarbossa Criteria (MSC) offer superior diagnostic accuracy for AMI in acute coronary syndrome (ACS) patients with LBBB.
Area of Science:
- Cardiology
- Electrocardiography
- Acute Coronary Syndromes
Background:
- The diagnostic value of new or presumed new left bundle branch block (LBBB) in identifying acute myocardial infarction (AMI) within the context of acute coronary syndrome (ACS) is debated.
- Left bundle branch block (LBBB) is observed in 3.3% of ACS cases and is linked to increased in-hospital mortality.
Purpose of the Study:
- To determine if the timing (new vs. old) of LBBB onset predicts AMI.
- To compare the diagnostic accuracy of LBBB timing against established ischemic electrocardiography (ECG) criteria, specifically the Modified Sgarbossa Criteria (MSC).
Main Methods:
- A systematic literature search of PubMed and Scopus was conducted for studies on ACS patients with LBBB up to December 2023.
- Diagnostic accuracy was assessed using sensitivity, specificity, likelihood ratios (LR+ and LR-), and diagnostic odds ratios (DOR).
- Risk of bias was evaluated using the Newcastle-Ottawa Scale (NOS) and QUADAS-2 tool.
Main Results:
- Differentiating new from old LBBB showed no significant diagnostic utility (LR+ 1.30, LR- 0.90, DOR 1.44).
- The Modified Sgarbossa Criteria (MSC) demonstrated high diagnostic accuracy for occlusive AMI, with 83.6% sensitivity and 92.6% specificity (LR+ 11.34, LR- 0.18).
- Studies included 51 research papers, analyzing incidence and mortality data alongside diagnostic performance.
Conclusions:
- The chronology of LBBB alone does not reliably predict the likelihood of AMI.
- Ischemic ECG criteria, particularly the MSC, offer significantly improved diagnostic accuracy and should guide clinical management of ACS patients presenting with LBBB.
Background:
The diagnostic utility of new or presumed new left bundle branch block (LBBB) for acute myocardial infarction (AMI) in the setting of acute coronary syndrome (ACS) remains controversial.
Objective:
To evaluate whether the timing of LBBB predicts AMI and to compare its diagnostic accuracy with ischemic electrocardiography (ECG) criteria, particularly the Modified Sgarbossa Criteria (MSC).
Methods:
We searched PubMed and Scopus for studies involving patients with ACS with LBBB through December 2023. Sensitivity, specificity, positive (LR+) and negative (LR-) likelihood ratios, and diagnostic odds ratios (DOR) were calculated to assess diagnostic accuracy. Incidence and mortality data were also analyzed. Risk of bias was evaluated using the Newcastle-Ottawa Scale (NOS) and the revised Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool.
Results:
A total of 51 studies were included. LBBB occurred in 3.3% of ACS presentations and was associated with higher in-hospital mortality. Differentiating new from old LBBB was diagnostically neutral: LR+ 1.30 (95% CI: 0.75 to 1.85), LR- 0.90 (95% CI: 0.79 to 1.02), and DOR 1.44 (95% CI: 0.93 to 2.24); all confidence intervals crossed the null value of 1.0. In contrast, MSC demonstrated 83.6% sensitivity (95% CI: 55.4 to 95.5%) and 92.6% specificity (95% CI: 78.9 to 97.7%) for angiographically confirmed occlusive AMI, with LR+ 11.34 (95% CI: 3.67 to 34.99) and LR- 0.18 (95% CI: 0.054 to 0.575).
Conclusion:
LBBB chronology alone does not significantly impact the likelihood of AMI. Ischemic ECG criteria - especially the MSC - provide substantially greater diagnostic accuracy and should guide clinical decision-making in ACS patients with LBBB.
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